The Geographic Information System (GIS) is known as a technology for comprehensively managing and processing data (spatial data) containing information relating to a location by using a geographic location, and for displaying the data visually thereby to allow advanced and rapid judgment. There is proposed an information management system for associating an object (land or building) displayed on an electronic map with a document file relating to the object via a computer system (for example, see patent document 1). In the information management system, the GIS for linking map information and attribute information collaborates with a document file system for managing document files containing detail information of objects. In order to allow easy access to the map and documents, an object ID is given to each object, a unique document ID is given to each document and the object IDs and the document IDs are linked on one-to-one basis in a document link database.
Here, in a railway or a road and its surrounding area, there exist numerous infrastructures (hereinafter referred to as “railway and other facilities”) managed by infrastructure owners or operators. Among the railway and other facilities, railway facilities may include stations, tunnels, bridges, tracks, railway crossings, traffic signals, various pole braces, kilometer post signs (kilo Post), CTC devices, train radio base stations, and other equipment. Besides, the road facilities may include traffic signals, tunnels, bridges, elevated bridges, service areas, information boards, kilometer post signs (kilo Post) and other equipment.    [Patent document 1] Japanese Patent Application Laid-open No. 2003-167919 (related art)    [Patent document 2] Japanese Patent Application Laid-open No. 2006-321277 (related art)